Test

The goal of this test was to show, how copying the message data (on the application level) affects the latency. One test was standard ØMQ latency test (local_lat and remote_lat) the other one was modified version of the test that copied the message data once on each peer.

The test results were provided by Michael Santy.

Environment

ØMQ/2.0 beta 2

CPU: Intel Core i7 940 @ 2.93 GHz

Memory: 12GB DDR3 @ 1333 MHz

IB HCA: Mellanox MT25204 — InfiniHost III Lx HCA

IB Switch: Mellanox MT47396 Infiniscale III

OS: Centos 5.4 x86_64

OFED: 1.4.1

libSDP: 1.1.99

Results

message size

latency with copying

latency w/o copying

4 kB

45.856 us

45.471 us

8 kB

55.690 us

57.462 us

16 kB

81.309 us

79.635 us

32 kB

99.423 us

97.009 us

64 kB

164.521 us

152.227 us

128 kB

227.577 us

192.544 us

256 kB

371.325 us

307.026 us

512 kB

682.949 us

528.641 us

1 MB

1464.738 us

1125.205 us

2 MB

2697.648 us

2085.429 us

4 MB

5045.856 us

3714.495 us

8 MB

9662.857 us

7199.121 us

16 MB

20898.646 us

13861.691 us

32 MB

44297.914 us

27565.414 us

64 MB

87754.242 us

54715.375 us

128 MB

167838.859 us

108787.906 us

256 MB

327360.406 us

216642.000 us

Here are the results of the test in the form of graph. Red line represents latency with copying, while the black line represents latency without copying:

The same results displayed in log/log graph to make the smaller message sizes more readable: